1. Field of the Invention
The present invention relates to a stepping motor driving apparatus used in an office automation appliance, a communication equipment, an audio appliance, a measuring instrument, etc.
2. Description of the Prior Art
A stepping motor driving apparatus is known from, for example, Japanese Patent Laid-Open Publication No. 6-38593 (1994). FIG. 3 shows an arrangement of this known stepping motor driving apparatus. The known stepping motor driving apparatus includes a stepping motor 1, a pointer 2 associated operatively with rotation of the stepping motor 1, a stopper 3 for stopping the stepping motor 1, an updown counter 4 for counting up or down step signals in accordance with rotational direction of the stepping motor 1, a ROM 5 for storing data on an excitation signal corresponding to a count of the updown counter 4, a digital-to-analog converter 6 for converting the data of the ROM 5 into a voltage signal and a drive amplifier 7 for driving the stepping motor 1 by amplifying the voltage of the digital-to-analog converter 6.
In FIG. 4 illustrating a speedometer of the known stepping motor driving apparatus by way of example, the pointer 2 of the stepping motor 1 is displaceable through a stroke angle S between an initial position A of an angular scale "0" and a final position B of a maximum angular scale "200" and the stopper 3 is disposed at the initial position A. When the stepping motor 1 is, for example, reset after power failure, the pointer 2 is returned to the initial position A. If a rotational position C of the stepping motor 1 is not known at this time, the stepping motor 1 is rotated counterclockwise towards the stopper 3 through a predetermined angle not less than the stroke angle S and thus, the stepping motor 1 can be stopped at the initial position A by the stopper 3. However, at this time, such a problem arises that since the predetermined angle not less than the stroke angle S is larger than an angle required actually for stopping the stepping motor 1 at the initial position A, i.e., an angle from the rotational position C to the initial position A, the pointer 2 is vibrated at the stopper 3.